I woudn't consider Mega Man having high speed, but last I saw he is considered A tier (for... reasons?) and I wouldn't say Young Link lacks power - that little toublemaker can kill at unreasonably low percents, but he does illustrate just how powerful of a balancing mechanic a bad recovery is. He isn't unapproachable like Mega Man, Snake or Sonic, and really does a great job hybridizing the zoner/rushdown gameplay - you can be as explosive or as campy as you want with him and it's a thing of beauty - but once you get sent offstage, that's where you're going to have a terrible time coming back as long as your opponent isn't playing someone with zero prospects offstage. Young Link is a great comparison that I often forget about, thanks for bringing him up.
Like I mentioned in my last post, so much more goes into balancing a character than how fast they run. Air speed, recovery potential, how fast moves come out, how long they're active, how big they are, out of shield options... the list goes on. To a casual observer, characters can seem completely overpowered but with more dedicated attention, glaring flaws become obvious.
Pikachu and Jigglypuff, and probably to a lesser extent Mewtwo became the Smash picks because they're the faces of the games thanks to the anime, but Lucario feels a bit up in the air (he was a big focus of that one movie, and they sure tried to push him in Gen 4 and 6), and Sakurai has basically admitted that with Greninja and Incineroar the process was more akin to "haha drawing look cool". It's a good point to make that undeniably, the popularity of a character
outside of the game made them the series icon, especially for Smash, and it carries over to my earlier comparison between ARMS and F-Zero. F-Zero has no main character - it's got a lot of lore, little of which is told through the gameplay, and tons of characters with different goals, moralities, and even species. The main four characters are Captain Falcon, Pico, Samurai Goroh, and Dr. Stewart - these four are prominent on every F-Zero box art aside from the GBA games, and before Falcon's introduction in Smash, the most unlikely rep probably would have been Dr. Stewart because the original manual described him purely as a racer, not a bounty hunter like Falcon, apparent green murder man like Pico, or rival bounty hunter Goroh.
Falcon stood out in F-Zero because of the comic book that was included in the instruction manual - he was made the main character in that short publication, likely due to Nintendo wanting to make him their mascot as they tried to "grow up" with their audience. Something about Captain Falcon is that his name is a title, at least as far as the anime is concerned - and it was brought to my attention today that Spring Man shares that trait - explained in
this comic. The similarities between the two franchises are really something else.
This is why I think that unless they're trying to go for
exactly what the fans want, which by the numbers would be Min Min, we're going to get Spring Man - he's the main character of the game
outside of the game. He's the one we're supposed to be interested in and that we're supposed to root for. That's why they picked him as an assist trophy in the first place.